A human gene probably responsible for Batten s disease has recently been cloned. This is a very serious disease causing neurodegeneration and death in many children. The nature of the defect causing the disease is not known. This human gene, CLN3, has a homologue in yeast, BTN1. A btn1 null mutant is viable, but does have a subtle phenotype in that under some conditions the mutant is somewhat resistant to D-(-)three-2-amino-1-[p-nitropheny1]-1,3-propanediol (ANP). The investigators propose to investigate Batten s disease using yeast and the BTN1 gene as a model system. The P.I. s will investigate expression of normal and mutationally altered forms of Cln3p and Btnip, and will determine critical regions of the proteins. The subcellular location of Btnip will be determined using GFP or epitope tags. Proteins interacting with Btnip will be found using the two-hybrid system, as well as by isolating possible complexes using a GST-Ttnip fusion or Btnip tagged with poly-histidine. Genetic screens will be done to find other mutants resistant to APN, to find suppressors of btn1, and to find mutations that are synthetically lethal with btn1.